Officer Brad Schultz of Cook spotted one ice shelter on the west end of Lake Vermilion -- on 3 inches of ice.

And dark house spearing has begun on Lake Winnibigoshish, though that spelled trouble for people who used ATVs to haul their gear.

"Unfortunately, some of the ATVs and trailers fell though the thinner ice,'' according to officer Tony Arhart of Grand Rapids. No injuries were reported.

The warming trend last weekend didn't help ice conditions.

Near Hinckley, some lakes had 3 to 4 inches of ice at the beginning of last week.

"Toward the end of the week, thawing weather had compromised ice conditions and all areas became very unsafe for angling,'' reported conservation officer Bret Grundmeier.

The DNR says 4 inches of clear, hard ice is needed for ice fishing or other activities on foot, 5 inches for snowmobiles or ATVs, 8 to 12 inches for a car or small pickup and 12 to 15 inches for a medium-size truck.